§1. When the defense briefs and observations have been communicated to each party, either party is permitted to present responses within the brief time period established by the judge.
§2. The parties are given this right only once unless the judge decides that it must be granted a second time for a grave cause; then, however, the grant made to one party is considered as given to the other also.
§3. The promoter of justice and the defender of the bond have the right to reply a second time to the responses of the parties.
Source: Code of Canon Law (Vatican.va)